Opsonization through the alternate complement pathway. We are attempting to identify the serum protein deficiency in SCD patients which leads to deficiency in opsonization through the alternate pathway in these patients. Opsonization through the alternate pathway will be studied in sera from splenectomized individuals and newborn infants, and any defects detected will be correlated with the defect found in SCD, if possible. The nature and significance of serum opsonizing antibodies against H. influenzae, type b, and pneumococci. We are studying the response in opsonizing antibody to H. influenzae and pneumococcal otitis media using the patient's own infecting organism. Mechanisms of bactericidal activity in normal leukocytes. We are currently studying the role of superoxide anion, peroxide, and hydroxyl radical in the killing of phagocytized bacteria. We are attempting to show that chronic granulomatous disease leukocytes do not generate these bactericidal agents. Enhancement of phagocytic bactericidal activity in chronic granulomatous disease leukocytes by sulfa. We are trying to determine the mechanism for this enhancement and are beginning controlled clinical trials of sulfa drugs in these patients. The immune response to bacterial otitis media. We are attempting to measure the antibody response in the middle ear fluid to influenzal and pneumococcal otitis media in children, using indirect immunofluorescence.